Conventional fluid (e.g., water) pumps can be orientated in either a vertical or horizontal position, based on the direction of the shaft. Vertical pumps, units with a vertical shaft configuration, can be further segmented into either Dry or Wet pit construction and subsequently into either volute pumps, propeller pumps or vertical turbine pumps. Vertical turbine pumps include a motor that is mounted on some type of pedestal or motor support attached to the upper surface of a motor attachment member. The pump shaft can be either directly attached or coupled to the motor and extends downward toward the casing and impeller through a column support or vertical pipe arrangement. Depending upon the style of vertical pump the casing can be either a volute type (typically single stage with a scroll diffuser), or a vaned diffuser configuration (typically multi-stage). The impeller includes a plurality of impeller vanes that rotate with the motor and shaft increasing the exit velocity of the fluid. The impeller also creates a pressure differential while pumping the water from an inlet or suction end to an outlet or discharge end. The impeller of volute style pumps generally includes a radial impeller vane configuration which turns the fluid 90 degrees within the casing so as to direct the pumped fluid into the casing discharge, which is perpendicular to the casing suction. The impeller of a vertical turbine pump generally includes a mixed flow impeller vane configuration which turns the fluid greater than 90 degrees into the vaned diffuser casing, which continues turning the fluid until it is discharged 180 degrees from the inlet. The impeller of propeller pumps (typically single stage) does not change the direction of fluid flow and the fluid exits the impeller and casing 180 degrees from the inlet. Vertical pumps are used in several applications. For instance, water can be pumped up from the water table in agricultural irrigation. Additionally, water can be pumped from a river or lake for use in power plants. Additionally still, pumps can be used to pump water in reverse osmosis applications.
Propeller and vertical turbine pumps had been made out of a metallic material for ease of manufacturability. Unfortunately, the associated corrosiveness of metallic components affected the longevity of such pumps. Accordingly, volute pumps, which have been manufactured out of corrosion resistant non-metallic materials, are utilized when a vertical pump is used and corrosion is an issue.
Propeller and vertical turbine pumps include a vaned casing which contains a plurality of diffuser vanes disposed in the casing at a location downstream of the impeller. Similar to a volute, the diffuser vanes increase the flow area along the direction of fluid flow, thereby decreasing the velocity of fluid flow through the casing and increasing the head pressure. Furthermore, the impeller vanes of vertical turbine pumps are twisted so as to define combined axial and radial flow characteristics. Due to the complex geometry of the propeller and vertical turbine pump components, conventional propeller and vertical turbine pumps are not currently made from fiberglass reinforced molded non-metallic materials, because of to the inability to provide sufficient molds to manufacture these non-metallic parts. Specifically, because diffusers have two or more passages, diffusers have not been formed from a single part made of a homogenous material.
Attempts have been made, for instance by Simsite Pump Valve Co., to create vertical turbine pumps out of a single block forged of non-metallic corrosion resistant materials. However, the complex pump components, such as the impeller and diffuser, are machined from these single block forgings, without fiberglass reinforcement, utilizing multiple axis machine tools which limit the design and size of these components due to “line of sight” machining restrictions. Furthermore, current vertical turbine pumps that have certain non-metallic components also include certain wetted components that are made of metal, such as the discharge elbow.
What is therefore desired is an improved non-metallic vertical turbine pump manufactured from corrosion resistant fiberglass reinforced resins with parts which can be molded into a homogenous solid shape, and contain reduced wetted metal parts.